Mechanistic studies of the beneficial effects of Anshen Dingzhi prescription for PTSD treatment: roles of the FKBP5-IKKα-NF-κB-NLRP3 signaling pathway

Objective: Anshen Dingzhi prescription (ADP) is an effective remedy for treating post-traumatic stress disorder (PTSD); however, the mechanism underlying its beneficial effects is unclear. This study explores the roles of the neuroinflammation regulated by the FKBP prolyl isomerase 5 (FKBP5)-IκB kinase alpha (IKKα)-nuclear factor kappa-B (NF-κB)-NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) signaling pathway in PTSD. Methods: The primary components of ADP, including ginsenosides Rg1 and Rb1, were quantified using ultra-performance liquid chromatography. Twelve C57BL/6 mice were allocated to control (D0) and experimental groups on days one, seven, and 14 of single prolonged stress (SPS). Eighteen C57BL/6 mice were allocated to control, SPS, and MCC950, an NLRP3 inhibitor (5 mg/kg) groups. Finally, 24 C57BL/6 mice were allocated to control, SPS, paroxetine hydrochloride (PRX), or ADP (18.4 and 36.8 mg/kg) groups. Mice were administered MCC950, PRX, or ADP for 14 days. The open field test and elevated plus maze were used to evaluate anxiety-like behaviors, whereas fear memory extinction was evaluated using the fear memory test. Western blotting was employed to evaluate the expression levels of the FKBP5-IKKα-NF-κB-NLRP3 signaling pathway, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β. The expression of FKBP5 and NLRP3 was further confirmed by immunofluorescence staining. Results: The amounts of ginsenosides Rg1 and Rb1 in ADP were (96.85 ± 1.14) and (9.04 ± 0.22) µg/g, respectively. Compared with the D0 group, the levels of the inflammatory cytokine proteins, TNF-α, IL-6, and IL-1β were elevated 1.33- to 1.51-fold and those of FKBP5-IKKα-NF-κB-NLRP3 signaling pathway were increased 1.16- to 1.41-fold in the hippocampus of the D14 group (P < 0.05); the fluorescence intensity of FKBP5 and NLRP3 was also markedly increased (1.33–1.79-fold) in the hippocampus of the D14 group (P < 0.5). Notably, injection of MCC950 (5 mg/kg) reduced the levels of FKBP5-IKKα-NF-κB-NLRP3 (0.80–0.88-fold) and inflammatory cytokines (0.74–0.83-fold), thereby improving the PTSD-like behaviors induced by SPS (P < 0.05). In addition, ADP (36.8 g/kg) significantly improved PTSD-like behaviors and reduced levels of hippocampal inflammatory cytokines (0.70–0.79-fold) and FKBP5-IKKα-NF-κB-NLRP3 (0.50–0.79-fold) (P < 0.05) in SPS mice. Conclusion: The results suggest a potential therapeutic benefit of ADP in PTSD due to the inhibition of the FKBP5-IKKα-NF-κB-NLRP3 signaling pathway.